Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Jump from a mast?
A sailor climbs the mast of a sailboat to a point 3 meters above the water. It looks like a nice day for a swim, so he decides to jump from the mast into the water horizontal to the keel.
If the 80 kg man jumps up at an angle of 45 degrees and a speed of 3 m/s. The moment of inertia of the boat is 15,000 as taken about a line parallel to the keel at water level. By how much does the man clear the edge of the deck 2 m from the mast? Assume the deck edge is at water level.
1 Answer
- 1 decade agoFavorite Answer
Hey odu!
For this equation i am not sure how the moment of inertia comes into play so i'll solve it the best i can with kinematics:
I am assuming that the moment of inertia is not relevant because it's parallel to the keel. But would the resulting torque from the moment of inertia act as a torsional pendulum? If so, that may help in solving.
let # = delta
#y = (v0)t + (1/2)at^2
-3 = 3*sin45 t - .5*9.8 t^2
-4.9t^2+2.12t+3=0
using the quadratic equation...
t= (2 +/- sq.rt [63.2944])/9.8
t=1.02 seconds
#x = v0t + 1/2at^2
since there is only acceleration due to gravity in this situation, the acceleration in the x direction is zero, yielding:
#x = 3*cos45 t where t = 1.02 so....
#x = 2.16 m
therefore, he clears 2m by...
.16m ---> answer
i think this answers the question because it does not ask for any resulting angular acceleration of the boat after you jump off. So, i think that the moment of inertia does not affect the answer. Just the force of gravity is playing a part in this question, so just look at the kinematics aspect.
